A new study has found that “blood levels of tetrahydrocannabinol do not correlate well with the level of impairment”, and heavy marijuana use doesn’t consistently lead to “cognitive and psychomotor impairment”.

“Marijuana is the most widely consumed illicit substance in the United States, and an increasing number of states have legalized it for both medicinal and recreational purposes”, begins the abstract of the study, which was published in the journal Anesthesia & Analgesia, and epublished ahead of print by the National Institute of Health. “As it becomes more readily available, there will be a concurrent rise in the number of users and, consequently, the number of motor vehicle operators driving under the influence.”

With that in mind, the study examined “the cognitive and psychomotor effects of cannabis, as well as current policy concerning driving under the influence of drugs.” To do so, “The authors performed a MEDLINE search on the epidemiology of cannabis use, its cognitive and psychomotor effects, and policies regarding driving under the influence of drugs.”